Capillary endothelial barrier

The capillary endothelial barrier represents the integrated structural and functional elements that maintain vascular integrity and regulate the passage of substances between the blood and interstitium (Claesson-Welsh et al., 2021). This complex barrier consists of the endothelial glycocalyx, a carbohydrate-rich layer on the luminal surface; the endothelial cell monolayer, characterized by tight and adherens junctions; and the basal lamina (Reitsma et al., 2007). Key proteins such as vascular endothelial cadherin (VE-cadherin) and various claudins are essential for maintaining the paracellular seal (Dejana et al., 2009). In healthy physiology, these components prevent the leakage of plasma proteins and blood cells while allowing for controlled nutrient exchange. In diseases such as sepsis, diabetes, and cancer, these components are often degraded or dysregulated, leading to pathological vascular leakage and tissue edema (Woodfin et al., 2011). Therapeutic interventions target these components by either inhibiting permeabilizing factors like vascular endothelial growth factor (VEGF) or by using stabilizers that reinforce junctional integrity. For example, monoclonal antibodies like bevacizumab reduce permeability by blocking VEGF signaling, while corticosteroids can enhance the expression of junctional proteins. Consequently, these components are vital targets in managing conditions like diabetic macular edema, acute respiratory distress syndrome, and tumor-associated edema.

Other names

Capillary endothelial barrier componentsVascular endothelial barrierEndothelial junctional complexBlood-tissue barrierEndothelial glycocalyx

Stabilization of endothelial cell-cell junctions (e.g., vascular endothelial cadherin), inhibition of vascular endothelial growth factor (VEGF) signaling, and protection or restoration of the endothelial glycocalyx (Claesson-Welsh et al., 2021; Dejana et al., 2009).